Bearing caps are designed to receive a sensor element, such as an ABS sensor or a rotational speed sensor. An ingress of water leads to premature failure of the bearing assembly and subsequently, replacement of the wheel bearing. Therefore, the sensor element must be protected, or sealed, from water.
Some bearing caps are configured to have two open axial ends. For this configuration, the sensor element is received into a hollow cylindrical receiver and is sealed by an O-ring in the direction of the bearing cap in order to prevent the penetration of water or other substances from damaging the sensor element. The additional element of an O-ring is a drawback to this configuration and, in practice, it has proven that water may still enter into the interior of the bearing cap. Any ingress of water, however, leads to premature failure of the bearing assembly, which ultimately, must be replaced.
In another configuration, the receiver for the sensor element may be integrated into a top wall of the bearing cap and the receiver is closed on an axial end facing the bearing assembly by means of a bottom wall so that the receiver is of a “pot-shaped” configuration. However, in practice water or moisture collects in the sensor receiver and permanent contact of the sensor element held in the receiver, may lead to partial or complete loss of the sensor signal.